Deshaun Watson and Patrick Mahomes have posted eye-popping stats during their brief NFL careers but also have displayed their toughness.

Photo: Peter Aiken, Stringer / Getty Images

We marvel at the wonder.

The unbelievable, inspiring athleticism of Deshaun Watson and Patrick Mahomes.

Thrilling, backyard-like fun that constantly produces “Did you just see that?!” exclamations.

Between the lines. With a professional football in their hands. On their feet. Smoothly spinning free. Coolly tossing no-look passes like it’s the most simple sporting act in the world. Collecting touchdown after touchdown, soaking up yards, points and national TV highlights.

But three seasons after Kansas City jumped up in the 2017 NFL draft to take a Texas Tech gunslinger with the No. 10 overall pick and the Texans leaped forward to take a national champion at Clemson with the No. 12 selection, there is one underrated word that has come to define both 24-year-old franchise quarterbacks.

Tough.

The 6-2, 220-pound Watson often eludes everyone, makes your jaw drop and keeps waving his magic wand. But in 40 combined regular and postseason games, super-smooth D4 has also taken 135 sacks. Then there are all the punishing hits when an official takedown isn’t recorded, but Watson still ends up on his back.

“I knew the consequences behind what I was doing. By holding the ball, I was going to get hit,” Watson said Wednesday at NRG Stadium, describing a game-changing overtime play against Buffalo that pushed the Texans into the divisional round. “I knew I was going to do that and I just made a play. I just knew I was going to brace myself. And for those guys, and especially in that moment in the game, it was do or die. They were actually going to have to both pick me up and bring me down. I wasn’t going down on first contact.”

Mahomes’ three-year career has been even more storybook, thus far. The 6-3, 230-pound QB watched and waited as a rookie, while Watson soared in seven games, then suffered a season-ending ACL injury. A single start during Mahomes’ rookie season became a 2018 MVP campaign that broke records, redefined the modern passing attack and ended in overtime of the AFC Championship Game against New England, the eventual Super Bowl champion.

But Watson’s Texans knocked off Mahomes’ Chiefs at Arrowhead Stadium in Week 6 this season. And Mahomes went down a game later, dislocating a kneecap on ESPN’s “Thursday Night Football.”

Kansas City still went 12-4, edged the Patriots for a first-round bye and enters the divisional round as a trendy Super Bowl favorite, thanks to the toughness of a young QB who was doubted, questioned and criticized during the months leading up to the 2017 draft.

Toughness is a key component that forms the NFL’s shield.

“You don’t play this sport without being tough,” Chiefs coach Andy Reid said. “It’s a pretty rough way to make a living, as far as physically and mentally, actually.”

Mahomes’ toughness, like Watson’s, has also helped define his team’s 2019 season.

“When (Mahomes) hurt his knee in Denver, he wanted to come back in. He dislocated his kneecap and wanted to continue playing in the game,” Reid said. “Then he never missed a practice; he did the scout team. He made me and the doctors and trainer tell him to, ‘Sit down and relax here. You’ve got a serious injury and you’ve got to let it heal.’ But that’s the way he’s wired.”

Watson has been a part of 89 total TDs since the Texans answered the Chiefs’ trade up for Mahomes with a franchise QB of their own. Coach Bill O’Brien said Watson’s presence and poise made an impact on the Texans before he was even drafted. Three seasons later, Watson’s in-game heroics are best captured with a reference to a famous escape artist from the turn of the last century: Houdini.

But you will fail if you try to find another quarterback who consistently takes hits like Watson, because there is none. Watson also consistently lifts his body off the turf, keeps his Texans moving forward and refuses to relent, even when it’s 16-0 Buffalo or 17-3 Kansas City.

From 2013-16, the Texans became notorious for their endlessly rotating wheel of QBs. Since Watson replaced Tom Savage (remember him?) midway through Week 1 of the 2017 season, only a season-ending injury has gotten in Watson’s way, and he spent 2018 playing through a broken rib and partially collapsed lung.

Tough, tough, tough.

“The way that you become … a franchise quarterback, whatever you want to call it, is by being there every day,” O’Brien said. “Every day, every game, you’re available to your team, day in and day out, game in and game out. That’s big for your team. That’s big for your organization. Durability, the ability to get up after taking a tough hit and to take care of your body the following week — and get ready and get up … for the next game — is all a big part of it.”

Mahomes isn’t a true dual-threat, but he’s run for 500 yards and four TDs in 31 career regular-season games.

Watson can’t fully match Mahomes’ in-air wizardry. But the Texans’ QB has already thrown for more than 10,000 career yards and just led the most important comeback in franchise history.

There will be test after test after test Sunday.

This should just be the beginning of the Watson-Mahomes rivalry.

But if the Texans hang with the Chiefs again and a spot in the AFC Championship is up for grabs as the fourth quarter approaches?

This rematch at Arrowhead could come down to which QB is tougher, physically and mentally, on the 12th day of January.

Brian T. Smith is a sports columnist for the Houston Chronicle. He has won multiple Associated Press Sports Editors awards and been honored by numerous journalism organizations. Smith was a Houston Texans beat writer for the Chronicle from 2013-15 and an Astros beat writer from 2012-13. The New Orleans-area native previously covered the NBA's Utah Jazz (The Salt Lake Tribune) and Portland Trail Blazers (The Columbian), among other beats. He is the author of the book Liftoff, which documented the Astros' rebuild and 2017 World Series championship.